XML and Web Services low down Clay Shirky hits the current hype over XML and web services on the head. His points:
1) XML is not a standard, it's a standard to define other standards (i.e. an alphabet, not a language). This means that anyone claiming anything is open, standards compliant, or public domain just because it's in XML is either lying or doesn't know what they're talking about.
2) Interoperability does not exist because of business reasons, not technology reasons. Technology cannot "make" things interoperable. Things will only be interoperable when businesses i)want them to be or ii)can't stop them from being.
3) Technology is dumb and can't understand semantics or context. No "cloud" can solve this problem, not UDDI or WRLD or any other fancy contextual description markup. AI has failed to solve this problem for 50 years, and there is no hope in sight.